Ion-exchange resins containing quaternary ammonium hydroxide groups



United States Patent 'CoNiAlNhvG Q'UATER- NARY AMMONIUM HYDROX'IDE GROUPS Gaetan'o'F. DAlelio, Pittsburgh, Pa, a ss'ig'nor to Kopp'ers com an *lnc. ,*a coipurati0n *ot' unaware Application December 5, 1951, 'Serial No. 260,082

, 28 Claims. Ci. 260 2.1

No Drawing.

. This invention relates to new aniomexchangeresins.

copper from oils, the removal of iron and copper from acid liquors, various applications in analytical determinations and in catalyzing esterification, ester hydrolysis, sucrose inversion, etc., and even for the treatment of peptic ulcers.

Anion-exchange resins used for some of thesepurposes are disclosed in applicants U. S. Patent 2,366,008, assigned to the General Electric Company, which comp-rise aininated copolymers of mono-vinyl-aromatic compounds and divinyl-aromatic compounds, suchas prepared by the nitration of an insoluble, infusible styrene-divinyl benzene copolymer followed by reduction of the 'nitro groups to amino groups. Other anion-exchange resins which are available comprise phenylene diamine-formaldehyde resins, and the phenol-formaldehyde-diethylene-triaihine and triethylene-tetramine resins, etc. However, the eniciency of these resins is not sufiiciently 's'atisfacto'ry for many anion-exchange purposes.

Anion exchange resins of great utility have' no'w been found which comprise water-insoluble, infusible *resins containing quaternary ammonium hydroxide groups,-t'he resins comprising polymers having a plurality of units 'of the formula wherein R is hydrogen 'or"a methyl or ethyl 'g'roiip R is an alkyl or aralkyl group such as "methyl, ethyl, pro'pyl, 'butyl, amyl, benzyl,phenethy1, etc.; and Z is 'a cyclohexylene -alkyle'ne group. 7 w

Various examples of anion-exchange resins suitable "for the practice of this invention include polymers whichare derivable from'monomers having the following structure:

wherein R, R and Z are as-described above. Thus, the polymers of this-invention may be regarded as derivable from the followin monomers, although the polymers "are advantageously prepared 'indirectlyfrom other-types of monomers as illustrated hereinafter. I

j (1') Where Z is va cyclohexylene-alkylene igroup 'such as cyclohjexylene methylene, methylcyclohexylenemethylene, dimethylcyclohexylenemethylene, ethylc'yclohexyl- "ice 2 cue-methylene, 'cycloheXylene-et hylene, cyclohexylenepropylene, cyclohexylene-outylene, etc.

merizeo directly L0 resins having quaternary ammonium hydroxide groups. 'l'nus a typical resin I may be considered as derived by he polymerization or p-vmyl-cyclonex'yl-methyl t'rn'netnyl ammonium hydroxide A resin of this basic structure can be prepared by the polymerization or jpvinyl cyano-cyclohexane and subsequent reduction and exhausnv'e alkylauon or the polymer to give the's'aine type or resin having quaternary ammonium groups. 111 addition, the starting monomer tor this particular re'sinca'n'a'lso be p-cyano-styrene or p-vinyl cyanoc'yclohexene when the reduction is carried out under conditions which also give hydrogenation of the benzene or cyclohexene nucleus. Similar quaternary ammonium hydroxide resins can also be prepared by this indirect method from other cyano compounds having the formula CH2=CRZCN, wherein R is hydrogen or a methyl or ethyl group and Z -is a cyclohexylene, cyclohexylenealkyle'n'e,cyclohexenylene or cyclohexenyl-alkylene group. -ln"most cases the polymerizable monomer, or mixture of polymerizable monomers, which contains the quaternary ammonium hydroxide group, or a group convertibl thereto, is converted to an insoluble, infusible resin by copolym'eri'zation with one or more cross-linking agents. Cross-linking agents which are not necessarily equivalent but which are suitable for the purpose of this invention include various classes of hydrocarbon-type cross-linking agent's, e. g., those having a hydrocarbon nucleus, with or without. non-hydrocarbon substituents attached thereto, such as divinyl aryls, e. g., divinyl benzenes, divinyl hapthalenes, divinyl toluenes, divinyl xylenes, divinyl 'chloro-benzenes, divinyl diphenyls, etc. or other hydrocarbon-type cross-linking agents, such as butadiene, chloroprene,'is'oprene, cyclopentadiene, isopropenyl styrenes, 'diisop'r'openyl benzenes, vinyl-cyclohexene, 1--phenylbutadiene, 2-phenyl-butadiene, etc. Any substituents attached to the hydrocarbon nucleus of these cross-linking agents should be such as will not interfere with any or the steps of preparation or use of the anion-exchange resins. When these hydrocarbon-type cross-linking agents are used, it is generally advantageous to use about 2-25 per cent by weight of the cross-linking agents. In some cases, however, ins'olubility and infusibility may be imparted to the resin by'the use of a monomer which has orwill, give the structure shown in the formula above and which also-has more than one polymerizable group, e. g., by' sta'rting with divinyl-cyano benzene, etc., which can be used alone or with other monomers having quaternary ammonium hydroxide groups or groups which can be converted thereto. a

In other cases it is'even possible to have the cross linking effected by analkylene or aralkylene group connecting two -polyjrner chains by attachment to a nitrogen in each chain. Generally, this type of cross-linking may not be preferred since some of the quaternary ammonium hydroxide groups are thereby restricted in their movements and are therefore not so easily accessible for anion exchange activity. The latter type of cross-linking may be accomplished, during or subsequent to the exhaustive alkylation, either by the use of a polychloroalkyl, aryl polychloroalkyl, or poly-chloroalkyl-aryl compound, such as dichloroethylene, phenyldichloroethylene, di-(chloromethyl)-benzene, etc., or by the use of a polyhydric alcohol as a solvent in the reduction of a cyano group to an amine. Moreover, it is often permissible to have somewhat similar linking accomplished by the formation of secondary amines, sometimes during the reduction of cyano groups, etc., to give ultimately cross-linking of the type R -CEr-&-

l l TRZOH z -CH2-(J- In this latter event, an R of the formula becomes a CH2([3(R)Z group.

In the preparation of these quaternary ammonium hydroxide resins from polymers containing cyano or other groups reducible to amino groups, any convenient method of hydrogenation may be used to convert the nitrogencontaining groups to amino groups. Such hydrogenations may be activated by various well-known hydrogenation catalysts including palladium on charcoal, Raney nickel, platinum, cobalt, nickel, copper, aluminum, iron, zinc, etc. With some compounds, for example certain cyanides, oximes and hydrazines, reduction to amines may be accomplished by the use of sodium and an alcohol such as ethanol. Moreover, iron and water catalyzed by ferrous chloride may be used to reduce nitro compounds to amines. In some cases exhaustive or partial alkylation may be carried on simultaneously with the reduction by the use of alcohol solvents corresponding to the alkyl or aralkyl group desired for the alkylation.

For certain purposes which do not require anioncxchange resins of the highly basic character of the quaternary ammonium hydroxide resins, the intermediate resins of this invention can be used quite satisfactorily. For example, cross-linked copolymers of vinyl cyanocyclohexane, vinyl cyanomethyl cyclohexane, vinyl cyano cyclohexene, vinyl cyanomethyl cyclohexene, cyanostyrene, cyanomethylstyrene, dicyanostyrene, cyanodivinyl benzene, etc., when reduced to the corresponding cyclohexylene-alkylene amine compounds give insoluble anion-exchange resins such as cross-linked polymerized vinyl cyclohexyl-methyl amine, vinyl cyclohexyl-ethyl amine, etc. Moreover, the partially substituted amine intermediates have utility as anion-exchange resins, e. g., the monoand di-substituted amines such as the monoand di-methyl derivatives of polymerized vinyl-cyclohexylmethyl amine, vinyl-cyclohexyl-ethyl amine, etc. These amine resins can be regarded as having repeating units of the structure wherein R and Z are as above described, and R is hydrogen or an alkyl or aralkyl group. With such amine intermediates which are to be used per se as anionexchange resins, the cross-linking agents may be of the same type described hereinbefore as satisfactory for the quaternary ammonium hydroxide anion-exchange resins.

Where exhaustive alkylation of an amine is to be effected, this is accomplished by heating the amine with a slight excess of the proper number of molecular equivalents of alkyl halide or substituted alkyl halide selected to give the desired R group. The tetraalkyl ammonium salt thus produced is converted to the tetraalkyl ammonium hydroxide by reaction with alkaline reagents, such as aqueous or alcoholic sodium hydroxide or potassium hydroxide, aqueous sodium carbonate, etc. After anionadsorption, the exhausted resin may be regenerated by the use of the same type of alkaline solutions as used in the original conversion of the quaternary ammonium salt to the hydroxide.

Minor portions of certain other monomers such as iso butylene, styrene, chlorostyrene, etc., may be used with the aforementioned monomers. However, these latter monomers should not have functional groups which will interfere with the polymerization activities of the monomers or with the ion-exchange activity of the products, or which may be ruptured to give substantial decrease in length of monomer chains or in cross-linking. Moreover, the cross-linking agent which is used should not contain any such interfering functional groups.

Since the quaternary ammonium hydroxide groups are the active ion-removing groups in these products, it is advantageous that the major portion of the polymerization mixture be of polymerizable monomers containing quaternary ammonium hydroxide groups or groups convertible thereto. Instead of starting with a monomer mixture containing the cross-linking agent, it is also possible to add the cross-linking agent to partial polymers of these monomers and to elfect cross-linking by subsequently completing the polymerization.

The following examples illustrate more particularly the above-described methods for preparing ion-exchange resins.

Example I Into a glass container are placed 7 parts of Turkey red oil, 300 parts of distilled water, 0.7 part of benzoyl peroxide, parts of 4-vinyl cyanocyclohexane and 10 parts divinyl benzene in the order named. The glass container is closed with a seal lined with aluminum foil and is revolved in a water bath heated at about 60 C. for about 30 hours. The peroxide polymerization catalyst is destroyed by adding about one part of a 10% aqueous solution of hydrazine. The dispersion is then transferred to a high pressure autoclave fitted with a stirrer and 5 parts of Raney nickel (see U. 8. Patent No. 1,628,190) is added thereto along with 30 parts of concentrated aqueous ammonia. The contents of the autoclave are then heated with rapid stirring at C. to C. while maintaining a pressure of. 750 pounds per square inch with hydrogen. The treatment is continued until absorption with hydrogen ceases. The insoluble, cross-linked polymer containing primary amine groups obtained by hydrogenation of the cyano groups is separated by filtration.

These amine groups are converted to the quaternary ammonium bromide form by suspending the resin in ethyl bromide in a container equipped with a reflux condenser and refluxing the mixture for approximately 24 hours. The resin containing the quaternary ammonium bromide groups is separated from the ethyl bromide by filtration and Washed with a small volume of a volatile organic solvent such as diethyl ether. Upon treatment of this resin with approximately /3 normal sodium hydroxide solution, there is obtained the quaternary ammonium hydroxide form of the resin.

Example II One hundred parts by weight of the resin of Example I is wet with 50 parts by weight of distilled water, and then lOO parts by weight of a standardized hydrochloric acid solution is added with shaking. After the resin and the solution have been in contact for about 15 minutes, the solution is separated from the resin by filtration. The filtrate solution is then titrated with sodium hydroxide to determine the amount of hydrochloric acid still in solution. If the filtrate solution has been completely neutralized by the resin, the procedure is repeated using a larger amount of the hydrochloric acid solution with a fresh sample of the resin. The efiiciency of the resin is determined by calculating the ratio of chloride ions actually removed from the solution to the chloride ions theoretically removable. A good efliciency is indicated by these calculations.

Example 111 The exhausted resin of Example II is regenerated by treatment with about /3 normal sodium hydroxide solution. After the solution is removed by filtration the resin is washed well with distilled water and retested for its anion-adsorption capacity according to the above-mentioned procedure. The elficiency after regeneration approximates the original capacity of the resin.

Example.

One hundredparts ofa resi'n obtained by-pol'ymeri'zing 4-vinyl cyano-cyclohexane and reducing it to the amine form as described in Example} are. cross-linked by treating at reflux temperature, with parts 1,2-dichloroethane. There is obtained a water-insoluble resin cross-linked through a portion of; the amino nitrogen atoms of the resin.

"This resin isadmixed-with excess; ethyl bromide and maintained atreflux temperature for approximately one day-to effect exhaustive alkylation. 'There is. obtainedthe quaternary ammonium bromide of the resin. Upon treatment of this resin with approximately normal sodium hydroxide solution there is obtained the quaternary ammonium hydroxide fOIIl'l'Of the'resin.

This resin is tested by the; procedures outlined in Examples II and III and efficiency of slightly less than that of the resin described in Example I is indicated.

Example V- To-9 0;parts vinyl cyclohexylmethyl triethyLamrnonium hydroxide and, 10; parts; divinyl. benzene; is added; 1'. part benzoyl'peroxide and, themixture, is maintained ;at: 60 C. fonabout one week. The insoluble, infr'usible resin .which is obtained is comminutated and is tested accordingztoithe procedures outlined in Examples H and III.. A good efficiency, isindicated;

The quaternary ammonium hydroxide.-resinsgofithis invention' are: very, efficient. anion-adsorption; agents. due very likely 'to: thev highly basic character of; the quaternary ammonium hydroxide groups. Other'anionswhichimay. be; removed: from. solution by: the; watereinsoluble polylers-of this, invention, vin additionpto the chlorideanions previously mentioned, include nitrate ions, sulfate ions; acetate, ions, oxalate ions,.. tartratev ions; on any other anions which will: reacts with. the basic quaternary. am= monium hydroxide groups in the resin to form-insoluble salts. Apparently because of the highly basic character of the quaternary ammonium hydroxide groups, these resins are moreefiicient than the ,preyiously used aminetype anion-exchange resins. 'These anion-exchange resins can: be readily regenerated by'washing with a dilute allpali solution, preferably, of an; alkali-metal hydroxide which forms soluble salts with the adsorbed anions.

The cross-linked copolymers suitable for the practice of this invention can be prepared by any method which will give infusible, insoluble resins, for example, by mass, solution, emulsion or suspension polymerization. The polymerizations may be advantageously catalyzed by various types of catalysts, such as peroxides, e. g., benzoyl, hydrogen, acetyl, acetyl-benzoyl, phthalyl, lauroyl peroxides, tert-butylhydroperoxide, etc.; other per-compounds, e. g., ammonium persulfate, sodium persulfate, sodium perchlorate, etc.; and in some cases the Friedel-Crafts type catalysts, such as aluminum chloride, advantageously at low temperatures.

Inert material, such as diatomaceous earth, Alundum, coke, silica, cinders, porous glass, etc., may be used as a carrier for the resin in order to increase the effective surface of the resin for ion-exchange. These carriers may be introduced by adding them any time prior to complete polymerization of the monomers to an infusible, insoluble state. An emulsion or dispersion type of polymerization is advantageous for the coating of such carrier materials with the resin.

The invention as hereinabove set forth is embodied in particular form and manner but may be variously embodied within the scope of the claims hereinafter made.

This application is a continuation-in-part of application Serial No. 117,729, filed September 24, 1949, now abandoned.

I claim:

1. A water-insoluble resin comprising a polymer having a plurality of repeating units having the structure wherein R is a member of the class consisting of hydrogen and methyl and ethyl groups; R is a member of the *6 classconsisting': of alkyl; andnlarall ytsg 2, represented by the formula: .r I

in which X and Y are members oftlie classcoiisisting' of hydrogen and methyl and. ethyl; n is a whole number less than 5; and O is a radical chosen from the group consisting of cyclohexyl and cyclohexenyl.

2. A water-insoluble resin of claim 1, in which the polymer has cross-linked polymer chains.

3. A water-insoluble. resin of claim 1, in which the polymer is a polymer of vinyl-cyclohexyl-methyl trialkyl ammonium hydroxide.

'4. A water-insoluble resin=of' claim 3,:Whichat wco n tains-a divinyl benzene nucleus in thepolyinernroleculez 5. A water-insoluble resin of claim 3 ,'in which the polymer is apolymer of. vinyl cyclohexyl methyf t'riethyl' ammonium hydroxide. i

6. A water-insoluble resin of claim-81in which the polymer is a polymer of vinyl-cyclohexyl methyl [tri- -methyl ammonium hydroxide.

7. A water-insoluble resin of.claim 6; which also contains a divinyl benzenev nucleus in' the polymer molecule. I

8. A Water-insoluble resin of claim 1", iii-which the polymer is apolymer of vinyl cyclohexy1ethyl= trir'lkyl ammonium hydroxide. I i

9. A water-insoluble resin of-'claim- 8, .Which also" cori tarns a divinyl benzene nucleus in the polymer-molecule.

l0. A- water -insoluble resin of; claim 8, in whichgthe polymer is a polymer of vinyl-cyclohexyl ethyltrimethyl ammonium hydroxide. A

11; A- water-insoluble resin" of claim 1 8,- in whichi'tliej' polymer IS a polymer of vinylecycloliexyl-etliyltriethyl ammonium hydroxide} A I I 12. A water-insoluble, resin of claim 1; in Wlricliithe" resin is in beadform.

13. An inert carrier coated ='with' =awatr-in'solirbleresin of claim 1.

14. A process for preparing water-insoluble, anionexchange resins comprising the step of exhaustively alkylatmg with an agent capable of furnishing groups chosen from the class consisting of alkyl and aralkyl groups the amino groups of polymeric material and converting the alkylated product to quaternary ammonium hydroxide derivatives, said polymeric material having repeating units of the structure wherein R is a member of the class consisting of hydrogen and methyl and ethyl groups; R is a member of the class consisting of hydrogen and alkyl and aralkyl groups; and Z 1s represented by the formula:

in which X and Y are members of the class consisting of hydrogen and methyl and ethyl; n is a whole number less than 5; and O is a radical chosen from the group conslsting of cyclohexyl and cyclohexenyl.

15. A process for preparing water-insoluble, anionexchange resins comprising the steps of exhaustively alkylating with an agent capable of furnishing groups chosen from the class consisting of alkyl and aralkyl groups the ammo groups in a polymeric amine and thereafter converting the resultant quaternary ammonium salt groups to quaternary ammonium hydroxide groups,

said polymeric amine containing repeating units having the structure wherein R is a member of the class consisting of hydrogen 21nd gllethyl and ethyl groups; Z is represented by the orm a:

in which X and Y are members of the class consisting of hydrogen and methyl and ethyl; n is a whole number less than and O is a radical chosen from the group consisting of cyclohexyl and cyclohexenyl; and R" is a member of the class consisting of hydrogen and alkyl and aralkyl groups.

16. A process of claim 15, in which the polymeric amine has been cross-linked by a hydrocarbon crosslinking agent.

17. A process of claim 15, in which the polymeric amine has been cross-linked by a divinyl aryl compound.

18. A process of claim 15, in which the polymeric amine has been cross-linked by a divinyl benzene.

19. A process of claim 15, in which the polymeric amine contains repeating units having a structure identical with a vinyl aminomethyl-cyclohexane.

20. A process of claim 19, in which the polymeric amine has been cross-linked by a divinyl benzene.

21. A process of claim 15, in which the polymeric amine contains repeating units having a structure identical with a vinyl aminomethyl-cyclohexene.

22. A process of claim 21, in which the polymeric amine has been cross-linked by a divinyl benzene.

23. The method of treating liquid media to remove anions therefrom which comprises contacting said media with a water-insoluble resin comprising a polymer having a plurality of repeating units of the structure wherein R is a member of the class consisting of hydro gen and methyl and ethyl groups; R is a member of the class consisting of alkyl and aralkyl groups; and Z is represented by the formula:

in which X and Y are members of the class consisting of hydrogen and methyl and ethyl; n is a whole number less than 5; and O is a radical chosen from the group consisting of cyclohexyl and cyclohexenyl.

24. The method of claim 23, in which the polymer also contains a divinyl benzene nucleus in the polymer molecule.

25. The method of claim 23, in which the polymer is a polymer of vinyl-cyclohexyl-methyl triethyl ammonium hydroxide.

26. The method of claim 23, in which the polymer is a polymer of vinyl-cyclohexyl-methyl trimethyl ammonium hydroxide.

27. The method of claim 26, in which the polymer also coiitains a divinyl benzene nucleus in the polymer molecu e.

28. The method of claim 23, in which the polymer is a polymer of vinyl-cyclohexyl-ethyl trialkyl ammonium hydroxide.

References Cited in the file of this patent UNITED STATES PATENTS Number 

1. A WATER-INSOLUBLE RESIN COMPRISING A POLYMER HAVING A PLURALITY OF REPEATING UNITS HAVING THE STRUCTURE 